What do piston rings do?

The piston ring is an engine component attached to the piston, precisely in the grove ring on the upper side of the piston. There are three piston rings for four-stroke engines, two for the compression ring and one for the oil ring. See the explanation for the various piston rings and their functions below.

1. Top compression ring (piston ring no. 1)
   Serves to prevent compression leakage in the combustion chamber. The top compression ring is also used to transmit heat and remove excess oil that is still attached to the combustion chamber wall for the first time.
2. Second compression ring (piston ring no. 2)
   Serves to prevent compression leaks in the second layer of the combustion chamber and transmit heat and clean the remaining engine oil that the top compression ring has missed. The No. 2 piston ring's function is similar to the No. 1 piston ring so that it acts as a back-up of ring No. 1.
3. Oil ring (piston ring no.3)
   Serves to collect and carry oil and lubricate the walls of the combustion chamber

Piston rings have a larger diameter than pistons, are shaped like rings but have elastic properties. When the ring and piston are inserted into the cylinder, this ring will expand and dock against the cylinder wall to close the existing gap.

Therefore closing this gap is considered a function of the piston ring in the engine. So what do piston rings do? The following article is about the function of piston rings that we know about.

1. Prevent compression leakage

The first piston ring's function is to prevent compression leaks in the combustion chamber, containing a mixture of air and fuel.

Compression in the combustion chamber greatly affects the condition and working of the engine. Too high compression can cause the engine to tingle, while less compression can result in loss of power or lack of power.

The piston ring, which is in charge of preventing compression leakage, is located at the top of the piston near the piston head and is often referred to as the top compression ring or piston ring no.1.

2. Prevents engine oil from entering the combustion chamber

The second function of the piston ring is to prevent engine oil from entering the combustion chamber. The compression rings no.1, 2, and partly by the oil ring to fulfill this function.

The compression ring usually has a tapered outer side (the side facing the cylinder wall). Because of its tapered shape, when the piston moves down the compression ring, piston ring number two will sweep all the engine oil on the engine's cylinder wall.

Meanwhile, the oil ring (ring no 3) often uses an expander (a ring that expands like a spring and has oil cavities around it). With the cavity around the ring, oil can enter and pass through the ring so that the cylinder wall lubrication process can occur.

That way, the cylinder walls can remain lubricated, but the engine oil does not penetrate the combustion chamber.

Also read:

• Why is my car blow white smoke from exhaust?
• Why is my engine oil mixed with coolant?

3. Transfers heat from the piston to cylinder wall

The last function of the piston ring is to transfer heat from the piston to the cylinder wall. This function is mostly carried out by compression rings No.1 and No.2.

Yes, these two compression rings have a function to transmit the heat that occurs during combustion from the piston to the cylinder wall.

As we know, the combustion process will produce a very high heat in the combustion chamber and the piston, whose surface is the place to receive very high pressure and heat.

Therefore, these two piston rings are used to transfer the piston's heat to the entire cylinder wall of the engine. That way, the temperature at the top surface of the piston can be more stable.